The present invention relates to a ventilation arrangement for a wind turbine rotor hub, and more specifically to a ventilation arrangement that does not require cutting additional holes in the nosecone.
Many installations inside the hub of a wind turbine rotor produce heat during operation. In particular, heat sources inside the hub may be relays installed in switch cabinets, batteries, chargers for batteries, pitch drive motors, pitch gear boxes, pitch drive controllers, and hydraulic units, as well as the main shaft bearing in some designs. However, reliable operation of several components is only guaranteed within a certain temperature range. For example, electronic circuits or batteries may malfunction at excess temperatures. Due to the several heat sources inside the hub, overheating problems of these components may occur, especially during summer.
Wind turbines may also be upgraded with blade tip extensions to increase the rotor diameter. Increased rotor diameter allows for increased energy production and use in lower wind speeds. However, the larger diameter rotor also causes increased heat generation in the hub, due to greater loads on the pitch system, battery boxes and hub control system.
To solve these overheating problems, ventilation holes are provided in the hub of some wind turbine designs. However, these ventilation holes are relatively small since, otherwise, water may leak into the interior of the hub through the ventilation holes. Of course, this is unfavorable in view of the sensitive electrical and mechanical installations in the hub. Therefore, only a small amount of heat can be exchanged through the small ventilation holes but the cross-sectional area of the ventilation holes cannot be simply enlarged.